Paper-box construction



H. B. SMITH PAPER 130x CONSTRUCTION Filed D99. 10, 1920 Patented @et. 9,

HARRY BIBIIDGMAN SMITH,

01F BROOKLYN, NEW YORK.

PAPER-BOX CONSTRUCTION.

Application filed. December 10, 1920. Serial No. 429,830.

' used in uncovered condition, but are espeiii cially desirable for covering by the tight Wrapped method. 7

Box shells of desirable simplicity and cheapness, of the unstayed type, have been produced by providing side wings of the cardboard shell blank with integral corner laps which are folded over and secured to marginal portions of the end wings. But box shells of this sort cannot be satisfactorily covered by the tight wrapped method because the shoulders produced by the thick edges of the corner laps create unsightly ridges in the cover paper; and tight wrapped boxes of this sort are, therefore, not acceptable to the trade.

This difficulty may be obviated by reducing the thickness of the corner laps, by removing portions of the blank material from areas of the under (outer) surface of the blank. The corner laps are thus reduced to such thickness that their edges do not produce any considerable or observable irregularity in the cover paper where it over lies the corner laps. The material may be removed from the blank by skiving or grinding. The box shell blanks are cut from cardboard, which is a compressed fibrous material capable of being quite readily split or separated into layers, and when such splits are started they are extended with comparative case. In the production of the cardboard the surface material is compressed to a relatively greater density, and is rolled or smoothed into greater homogeneity than the inner portions of the material, so that while the cardboard may not actually be built up in layers, it tends to separate quite readily in layers, and especially so that the surface material at either side of the sheet may be split away from the sheet body. When corner laps are reduced in thickness by the method above described, the inner surface layer of the blank is left intact Kings and the material is cut away at the opposite side, and when'the corner laps are pasted agalnst the end wings of the box, the line of connection between the cut surface of the lap and the body of the blankis directed outward. When pressure. is exerted within the box, as for example by packing it too full, or by handling it too roughly, a split readily starts at this outwardly directed intersection between the lap and the wing body and the, spliteasily extends until the side wing tears completely away from its proper position, or bulges outward to such an extent that the utility of the box is destro ed.

y invention avoids the diiiiculties and disadvantages mentioned by removing material from the corner laps on the upper (inner) side of the blank, thus leaving the corner lap in the form of an integral continuous layer of the outer surface material of the blank. When the box shell is bent up into proper form and the corner laps glued to the end wings, the connection between the side and end wings is made by a continuous outer surface portion of the blank material, and any bulging strain applied to the box sides or ends is resisted by the full tensile strength of the surface material constituting the corner lap, without the pos sibility of a split starting where the lap joins the side wing.

When the corner laps are formed in the manner described, the vertical corners of the shell may be made sharper than by the previous method. The end wall construction may be made very smooth, since the thickness of the corner laps may be reduced to such an extent that they produce no appreciable bulge in the cover material. The laps are more easily and eflectively secured to the end wings because the material cut away from the laps leaves a relatively rough surface which readily takes up the adhesive and adheres with greater tenacity to the end wings when the glue is set. The thinness and flexibility of the'laps also enables them to conform more readily and perfectly to the surface to which they are applied, and the tendency of the laps to separate or spring away from the end wings soon after being applied is materially reduced, since the thin material at the corner bend does not exert the same force tending to straighten the laps out in line with the side wings as is the case when the corner laps have the same, thickness as the blank material.

The characteristics and advantages of the invention are further sufiiciently described in connection with a detail description of the accompanying drawing, which show certain exemplifying embodiments of the invention. After considering these embodiments persons skilled in the art will understand that variations may be made within the principles of the invention; and I contemplate the employment of any structures that are within the scope of the claims.

Figure 1 is a perspective view of a box shell blank embodying the invention,

Figure 2 is an edge view,

Figure 3 is a perspective view of one end of the box shell in set-up condition and uncovered,

Figure 4 is a similar view of one end of.

the complete covered box part,

Figure 5 is a horizontal section through one corner of the complete box part,

Figure 6 is a similar section showing a slightly modified arrangement of the corner lap and adjacent side and end'wing, the cover paper being omitted,

Figure 7 is a similar section showing another modified arrangement of the corner lap, and

Figure 8 is a horizontal section through one corner of the box having corner laps of reduced thickness produced by cutting 'material from the outer (under) side of the blank, to illustrate undesirable features of that arrangement.

The box shell blank of Figure 1 is cut froma sheet of cardboard or pasteboard and comprises a body portion 10, integral side wings 11 and end wings 12, and corner laps 15, usually integral with the side wings; although they may in some cases be integral parts of the end wings. The blank is creased or scored along the lines 16 to permit proper folding of the blank into box form. According to the previous practice, the corner laps 15 are of the same thickness as the material of the blank. and are bent in along their line of connection with the side wings and glued to either the inner or the outer surface of the end wings, usually the outer surface, as shown in Fig ure 3, to produce a complete box shell. A relatively stifi' fold is produced at the corner which exerts a considerable force tending to straighten out the corner laps, which will consequently separate from the end wings, producing an imperfect box part, unless considerable care is taken in pressing and retaining them in position until the adhesive has properly set. A marked variation of thickness occurs in the end of the box at the edges of the corner laps, and this variation is noticeable in the form of a ridge in the cover paper when the paper is applied and pressed down. It is impossible, therefore, to produce a tight-wrapped box of the highest quality with the shell construction as so far described.

To avoid the disadvantages, and to obtain the advantages previously mentioned, in my invention the blank material is removed or cut away from the inner surfaces of the corner laps, producing laps 15 of reduced thickness, in the form of a layer of blank material forming an integral continuation of the outer surface materialof the blank. The thickness of the corner laps may be varied as may be desirable, but usually sufiicient material is removed to make the thickness of the corner laps substantially less than that of the blank body, and frequently the corner laps are less than half as thick'as the blank material. The reduction in thickness of the laps may be in various forms but usually it is preferred, as shown in the drawings to make the corner laps of substantially the same thickness throughout, so that an appreciable shoulder is formed along the lines 20 where the corner laps join the side wings.

The adhesive is applied to the inner surfaces of the corner laps and the blank is bent up to the position shown in Figure 3, and the end laps pressed against the outer surfaces of the end wings. The roughened inner surfaces of the corner laps produced by the removal of the material take the adhesive readily and adhere quickly and firmly to the end wings; also the corner bend of the laps is in relatively thin material which has little or no tendency to straighten out and separate the laps from their proper position. The adjacent edges of the end and side' wings may be in either of the relative positions shown in'Figures 5 and 6. The shoulders formed along the lines 20, when the corner laps are of uniform thickness, as above described, assist in the proper location of the edges of the side and end wings as shown in these figures.

An alternative method of connecting the corner laps is shown in Figure 7, in which adhesive is applied to outer surfaces of the laps and the laps are turned in and secured to the inner marginal surfaces of end wings 12.

In any of the described arrangements of the corner laps it is evident that any force tending to bulge the sides and ends of the box outwardly is resisted by the full tensile strength of the corner laps 15 which consist of a suitable thickness of the outer blank material. There is no possibility of any internal strain, such as may be caused by overtightly filling the box or roughly handling it, starting a split at the line of juncture of v ed in the manner described simply tend to apply tensile strain to the lap material, and it is evidently impossible for the layers constituting the laps to peel or split away from the body of the blank.

F igure 8 shows corner laps 30, produced by removing material from the under (outer) surface of the blank. A bul ing strain has been applied to the side wal l1 and a split has thus been started at the point 35 where the lap material 'oins the ho y of the side wall. This split is readily started under the conditions shown by reason of the layering tendency of the pasteboard and especially by the tendency of the relatively tough and homogeneous surface material to split away from interior portions of the blank. A split thus readily started is likely to extend until the corner lap tears away entirely from the side wing or the side wing bulges so that the utility of the box is destroyed.

Fi ur'es A and 5 show the box shell produce in accordance with my invention finished by the application of a cover paper 40, usually by the tight-wrapped method. The projections produced by the edges 45 of the corner laps at the endsof the box are so slight that no appreciable irregularities in the cover paper are created, and the dey sired smooth and flat appearance of the cover is secured, as indicated in Figure 4. The thickness of all the parts is necessarily exaggerated in Figure 5, but this figure makes it apparent that the thickness of the corner laps is not necessarily very much, or any, greater than the thickness oi? the cover paper; and consequently when the materials are of normal thickness no perceptible irregularity is produced by the overlapping of the cover paper either upon itself or upon the corner laps.

My invention therefore provides a box shell construction which may be completed by covering by the tight-wrapped method, to produce a complete box structure of the most approved and excellent type. The invention is not necessarily limited, however, to the tight-wrapped cover method since the shell construction described is valuable and desirable whether the shells are completed by covering or not.

I claim 1. A box shell blank having corner laps, upper surface portions of the lap material being removed to reduce the thickness of the lap.

2. A box shell blank of cardboard comprising corner laps of reduced thickness consisting of integral outer surface material of the blank.

3. A cardboard box shell blank comprising a body portion, side and end wings, and corner laps of reduced thickness extending from certain of the wings, the reduction in thickness of the laps being made on the inner side of the blank material.

4:. A cardboard box shell blank comprising a body portion, integral side and end wings, and corner laps of reduced thickness extending from edges of certain of the wings, the corner laps consisting of an in tegral outer layer of the blank material.

5. A cardboard box shell blank comprising a body portion, integral side and end wings, and corner laps of reduced and substantially uniform thickness throughout, extending from certain of the wings, said laps consisting of integral outer-layer material of the blank.

6. A box shell formed from a blank comprising a body portion, integral side and end wings, and corner laps adhesively secured to marginal portions of certain of the wings, the corner laps consisting of integral outer surface material of the blank reduced in thickness by removing inward portions of the blank material.

7. A cardboard box shell comprising a body portion, integral side and end wings, and corner laps of reduced thickness adhesively secured to marginal portions of certain of the Wings, said laps consisting of integral outer layer material of the shell.

8. A cardboard box shell formed from a blank comprising a body portion, side and end wings, certain of the wings having extended marginal portions cut away on-the inner surface ofthe blank to form corner laps of substantially reduced thickness, the roughened surfaces of the laps remaining after removal of material being adhesively secured to marginal portions of adjacent wings.

9. A cardboard box shell structure formed from a blank comprising a body portion, integral side and-end wings, and corner laps extending from certain of the wings, inner surface material of the blank substantially coextensive with the laps being removed to materially reduce the thick ness of the laps, shoulders being formed at the lines of juncture of the laps and Wings,

said shoulders being located against end edges of adjacent wings, and the corner laps being adhesively secured to surfaces of adjacent wings.

10. In box construction, a cardboard shell formed from a blank comprising a body portion, integral side and end wings, and corner laps of reduced thickness consisting of integral outer surface layers of the blank material, the corner laps being adhesively secured to marginal portions of adjacent Wings, and a tight wrapped cover characterized by the substantially flat and smooth appearance of end portions of the cover overlying the thin shell corner laps.

,11. A box structure comprising a' shell formed from a blank having a body poring characterized by substantially smooth and flat surfaces at the ends of the box structure overlying the corner laps. 10 Si ed at New York city, in the county of Ng iiv York and State of NewYork, this 23rd day of November, A. D. 1920.

HARRY BRIDGMAN SMITH. 

